We describe laboratory experiments to study the harmonic content of standing waves in guitar strings. The experimental data were taken by using the magnetic pickup from a guitar and a digital oscilloscope with a Fast Fourier transform capability. The amplitudes of the harmonics in the measured signal depend on the location where the string is plucked, resulting in a different timbre of the sound. The relative amplitudes of transverse standing waves in a string were determined from the experimental data and also predicted from the wave equation with the boundary and initial conditions corresponding to the initial shape of the string.

1.
M. C.
Wittmann
, “
The object coordination class applied to wavepulses: analyzing student reasoning in wave physics
,”
Int. J. Sci. Educ.
24
(
1
),
97
118
(
2002
).
2.
M. C.
Wittmann
and
E. F.
Redish
, “
Understanding and affecting student reasoning about sound waves
,”
Int. J. Sci. Educ.
25
(
8
),
991
1013
(
2003
).
3.
J. L.
Sandoval
and
A. V.
Porta
. “
Fourier analysis for vibrating string's profile using optical detection
,”
Am. J. Phys.
53
(
12
),
1195
1203
(
1985
).
4.
S. B.
Whitfield
and
K. B.
Flesch
, “
An experimental analysis of a vibrating guitar string using high-speed photography
,”
Am. J. Phys.
82
(
1
),
102
109
(
2014
).
5.
E.
Kashy
,
D. A.
Johnson
,
J.
McIntyre
, and
S. L.
Wolfe
, “
Transverse standing waves in a string with free ends
,”
Am. J. Phys.
65
(
4
),
310
313
(
1997
).
6.
W.
Haerbell
, “
Laboratory exercises on oscillation modes of pipes
,”
Am. J. Phys.
77
(
3
),
204
208
(
2009
).
7.
M. L.
Boas
,
Mathematical Methods in the Physical Sciences
, 2nd ed. (
John Wiley & Sons
,
Hoboken, NJ
,
1983
), p.
554
.
8.
Neo-D magnetic sound-hole pickup, Fishman Transducers, Inc., <http://www.fishman.com/products/details.asp?id=49>.
9.
D.
Politzer
. “
The plucked string: an example of non-normal dynamics
,”
Am. J. Phys.
83
(
5
),
395
402
(
2015
).
AAPT members receive access to the American Journal of Physics and The Physics Teacher as a member benefit. To learn more about this member benefit and becoming an AAPT member, visit the Joining AAPT page.